This section introduces aspects that may help facilitate a better understanding of the disclosure. Accordingly, these statements are to be read in this light and are not to be understood as admissions about what is or is not prior art.
Wireless power transfer (WPT) technologies are gaining increased popularity as they address key limitations associated with “tethered” and battery operated consumer and medical electronics including miniaturization, cost, and safety. Traditionally, WPT techniques are based on near-field magnetic induction or far-field radiofrequency radiation. Far-field techniques offer the capability to wirelessly power over a large coverage area but have low end-to-end efficiency due to high material electromagnetic (EM) interaction and 1/r^2 power density dependence. In contrast, near-field magnetic induction can operate at high efficiency but only within centimeter ranges. Recently, the development of magnetic resonance coupling (MRC) has gained momentum as a promising WPT method due to its capability of operating at much longer distances than traditional inductive methods while maintaining higher end-to-end power transfer efficiency than far-field radiative techniques. In addition, MRC systems demonstrate capabilities of power “relaying” and preferentially designed power distribution to multiple loads, features of which do not exist in traditional induction and far-field techniques. However, practical implementation of MRC has been challenging. Conventional MRC requires a minimum of four inductively coupled coils to generate the resonant structure of which the optimization parameters are difficult to control and are difficult to miniaturize. Furthermore, the coupled-mode theory and equivalent circuit model derived design equations are overly complex and become impractical as a design guide especially when incorporating “relay” coils and power distribution to multiple loads. Other methods utilizing direct coupled methods and impedance matching networks have been presented. However, among the current technology, there does not exist a unified and simple approach for achieving the optimal IM solution in MRC systems. This is especially apparent as systems become overly complex due to the addition of relay resonators.
Therefore, there is an unmet need for a novel arrangement and methodology in WPT utilizing MRC that allows for simple IM optimization and flexible design that can be reconfigured for when relay coils are being added.